Nature Medicine: There are advances in the early diagnosis of Alzheimer's disease

A large study led by Lund University in Sweden shows that Alzheimer's patients can now be identified before any symptoms appear
.
It is also possible to predict which patients will worsen
in the coming years.
The findings, published in the journal Nature Medicine, are timely
given the recent development of new drugs to treat Alzheimer's disease.

It has long been known that two proteins are associated with Alzheimer's disease, β-amyloid, which forms plaques in the brain, and tau, which accumulates
in brain cells later in the disease.
Previous diagnoses of Alzheimer's disease have been based on elevated levels of these proteins and cognitive impairment
.

Co-corresponding author Professor Oskar Hansson of Lund University said: "The brain undergoes changes 10 to 20 years before the patient develops obvious symptoms, and only when the tau protein begins to spread, the nerve cells die, and the patient has cognitive problems
for the first time.
This explains why Alzheimer's disease is difficult to diagnose
in its early stages.
”

Today, he leads a large international research project with 1,325 participants from Sweden, the United States, the Netherlands and Australia
.
At the start of the study, the participants did not have any cognitive problems
.
Through PET scans, the researchers observed the presence of tau and amyloid
in the brains of some of the participants.
At follow-up a few years later, they found that people with both proteins had a 20- to 40-fold
higher risk of developing Alzheimer's disease than people who didn't.

Rik Ossenkoppele, a researcher at Lund University and the University Medical Centre in Amsterdam, said: "When both β-amyloid and tau proteins are present in the brain, it should not be seen as a risk factor, but as a diagnosis
.
When a pathologist examines such a brain sample, the patient can be immediately diagnosed with Alzheimer's disease
.
He is the first author of
the study.

He explained that there are two schools of thought in the Alzheimer's research community: some believe that Alzheimer's disease can only be diagnosed when cognitive impairment is present, while others believe that diagnosis can be based purely on biological results and what
you see in the brain.
Ossenkoppele and his colleagues belong to the latter
.

"For example, you can draw an analogy
between our results and prostate cancer.
If you do a tissue biopsy and find cancer cells, even if the patient is not yet symptomatic, the diagnosis is cancer," Rik Ossenkoppele said
.

Recently, a new drug for the treatment of Alzheimer's disease, Lecanemab, has achieved positive results in clinical trials, and the drug has successfully completed the final stage of clinical trials
.
Based on this, the Lund University study is very interesting, the researchers believe:

"If we can diagnose the disease before cognitive impairment develops, then we could eventually potentially use this drug at a very early stage to slow disease progression
.
" Coupled with physical activity and good nutrition, a person will have a greater chance of preventing or slowing down future cognitive impairment
.
However, more research is needed before it can be recommended to those who
have not yet developed memory problems.
”

Original search

Ossenkoppele, R.
, Pichet Binette, A.
, Groot, C.
et al.
Amyloid and tau PET-positive cognitively unimpaired individuals are at high risk for future cognitive decline.
Nat Med (2022).
https://doi.
org/10.
1038/s41591-022-02049-x